Gas heater



FIG. 1 is a front view showing my new design in one embodied form;

FIG. 2 is a left side view of my design shown in FIG. 1;

FIG. 3 is a top plan view of my design shown in FIG. 1; and,

FIG. 4 is a bottom view of my design shown in FIG. 1.

The surface(s) or portion(s) of the article not shown in the drawing or described in the specification form(s) no part of the claim design. 

The ornamental design for a gas heater, as shown and described. 